1. Field of Invention
This invention relates to the art of methods and apparatus for preparing the edges of resilient elastomeric sheet material for splicing and especially to inner liners for tires.
2. Description of the Related Art
Heretofore inner liners have been applied to a tire drum and the end edges overlapped to provide a splice. This has not been satisfactory because the overlapping causes a heavy spot and results in an imbalance of the tire. To avoid this two layers of inner liner material have been wrapped around the tire drum. This is not economical because it requires twice the length of inner liner than is necessary. The other alternative has been to connect the end edges with a connecting strip. Here again the balance of the tire is adversely affected. When a butt splice of the inner liner end edges is used the lubricant applied to the tire building drum may be caught in a corner between the ends of the inner liner and this cause a crack in the inner liner which results in a defective tire.
Attempts have been made to prepare the edges of inner liners for splicing by crushing a section of the inner liner and then cutting that section which results in crushed end edges. In another prior art method and apparatus for preparing edges of reinforced elastomeric material a section of material clamped between spaced apart clamps is stretched by a wedge member and a knife is inserted through the wedge member to cut the material. The stretching is within the elastic range of the sheet material and heat is applied to retard the elastic recovery so that a reduced thickness of the edges is maintained during splicing. Also no provision is made for conveying the cut sections to another location.